Comparative%20refractive%20outcomes%20following%201.8%20mm%20bimanual%20cataract%20surgery%20versus%203.2%20mm%20coaxial%20cataract%20surgery

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Comparative refractive outcomes following 1.8 mm
bimanual cataract surgery versus 3.2 mm coaxial
cataract surgery

• M. Usman Saeed FRCOphth, Farrukh Ali FRCS,
• M.Salman Saeed MBBS, BV Kumar FRCS,
• Som Prasad FRCOphth, FACS

The first four authors have no financial interest
in the subject matter of this poster Som Prasad
has received travel reimbursements from Bausch
Lomb, Alcon, Novartis Pfizer
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The issue is whether two 1.8 mm incisions produce
a better refractive result than a single 3.2 mm
incision 2 side ports
1 x 2.75 mm incision enlarged to 3.2 mm 2 side
ports
2 x 1.6 mm incisions
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Coaxial versus Bimanual
Coaxial phacoemulsification Note small side-port
and main port with phaco probe and sleeve
Bimanual phacoemulsification Note 2 almost
equal sized ports and phaco probe without a
sleeve
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Method

• Retrospective review of pre operative, post
  operative and surgical notes of patients
  undergoing cataract surgery by one surgeon
• Prospective data collection on an electronic
  patient record database
• Appropriate departmental approvals were obtained
  before reviewing individual electronic records

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Method

• Data collection was done and converted to a
  microsoft excel spreadsheet
• Pre operative data and post operative data to was
  transposed to negative cylinder notation
• Refractive surgical effect was calculated for
  each patient considering the target refraction,
  post op refraction and pre op refraction

RSE formula as written by Mr. Stephen B Kaye
FRCOphth
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Method

• Group 1 (MICS) cataract surgery by bimanual
  micro-incision cataract surgery (MICS) with
  insertion of an intra-ocular lens implanted in
  the bag through a 1.8 mm superior incision.
• Group 2 (SICS) eyes had undergone cataract
  surgery using conventional coaxial
  phacoemulsification (SICS) cataract surgery with
  2.75 mm superior incision enlarged to 3.2 mm for
  IOL insertion.
• No other refractive procedures were undertaken
  simultaneously during surgery.

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Results

• 194 records were identified and included
• Group 1 Bimanual MICS n 97
• Group 2 Coaxial SICS n 97
• The intended post operative refractive aim for
  group 1 was -0.26 dioptres (average) and for
  group 2 was -0.21 dioptres (average).

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Group 1 Bimanual 1.8 mm MICS

• In Group 1 (MICS with 1.8 mm superior incision),
  the average aimed post operative refraction was
  -0.26 dioptres (range 0.3 to -1.12 dioptres).
• The mean of refractive surgical effect was -0.03
  dioptre sphere with 0.38 Dioptre cyl with a
  calculated nearest spherical equivalent of 0.16
  dioptres (average). (p0.0001)

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Group 2 Coaxial 3.2 mm

• In Group 2, (SICS with 3.2 mm superior incision),
  the average aimed post operative refraction was
  -0.21 dioptres (range 0.5 to -0.60 dioptres).
• The mean of refractive surgical effect was -0.31
  dioptre sphere with 0.66 dioptre cyl range with
  a calculated nearest spherical equivalent of
  0.02 dioptres (average). (plt0.00001)

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Target refraction versus post op refraction data
Target refraction Target refraction Target refraction Target refraction Refractive surgical effect Target aim RSE post op Refractive surgical effect Target aim RSE post op Refractive surgical effect Target aim RSE post op Refractive surgical effect Target aim RSE post op Post operative data Post operative data Post operative data Post operative data
NES Sphere cyl Axis NES Sphere Cyl Axis Nes Sphere Cyl Axis
Group 1 (1.8 mm) -0.26 -0.26 0 0 0.16 -0.03 0.38 177 -0.09 -0.26 0.34 177

Group 2 ( 3.2 mm ) -0.21 -0.21 0 0 0.02 -0.31 0.66 10.87 -0.17 -0.46 0.59 10.87

Difference between difference to target refraction in group 1 2 Difference between difference to target refraction in group 1 2 Difference between difference to target refraction in group 1 2 Difference between difference to target refraction in group 1 2 Difference between difference to target refraction in group 1 2 -0.04 0.36 115.2
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Conclusion

• Bimanual cataract surgery with 1.8 mm incision
  appears to induce a 0.38 dioptre change in
  astigmatism.
• Conventional coaxial phacoemulsification with 3.2
  mm incision appears to induce a 0.66 dioptre
  change in astigmatism.
• The smaller change in astigmatism associated with
  smaller incision size is statistically
  significant.
• This may be considered a step towards achieving
  astigmatically neutral corneal incisions.